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Belegedhel · 03-24-2014, 08:11 AM

I am in the rebuilding stages of a shell-off with my '73 Globetrotter. The rear street side lower segment was replaced at some point in the past. It has a very dull patina compared to the rest of the trailer, and I assumed this was because it had no clear coat on it and was able to oxidize. I also had a big messy dent in my curb side front lower segment, and after trying unsuccessfully to work the dent out, I replaced the segment with a brand new one. The trailer is made of 6061 T6, and I put a new panel in the center rear made of 6061 T6, which had a kind of brushed finish to it. I did a test polish spot on it, and it shined up really quick and easy, and matches the rest of the shell. The dull rear segment has been a pain, but it looks like it might shine up as well--just a lot of tough oxidization to get through.

That brand new segment in front looks like it is going to ruin my good time, though. I assume it is made of whatever modern alloy they make them of these days (5054? 3003/3004?), and accepted that it would not be a perfect match to the rest of the trailer. I did not figure that it wouldn't shine up at all. I tried a test polish spot on it, and after a good bit of polishing, it hardly looks touched. Has anyone out there tried and succeeded in polishing up a modern alloy segment?

Melody Ranch · 03-24-2014, 08:29 AM

How are you polishing it? That makes a BIG difference.

Belegedhel · 03-24-2014, 09:53 AM

My work so far has been done with just a Makita disc sander with a 6" cloth buffing wheel and a black compound bar. This setup takes the "mill" marks out of the flat panels quite quickly, but doesn't seem to have any impact on the "new" segment. I've put some aircraft stripper on the segment to confirm that it doesn't have any clear coat on it, and it appears to be clear coat free (unless the modern plasti-coat is so tough that aircraft stripper won't touch it).

InsideOut · 03-24-2014, 12:45 PM

Not sure if the Aircraft Stripper would take care of the modern plasticoat or not.

To determine if you do still have a protective coating:

wash a small test area with warm soapy water
let it dry
take a tiny dab of toothpaste and gently rub it on the clean skin with your finger
if it turns black > it's clean aluminum
if it doesn't turn black > there is still intact protective coating of some sort

If it is a different alloy, it will look different polished. It may seem the same at first, but with exposure to the elements it will oxidize differently. Good luck!

Shari

Belegedhel · 03-25-2014, 07:40 AM

Alrighty-then... I tried the old "toothpaste on the finger" technique described above, and it would appear that the new panel has clearcoat on both the interior and exterior. Aircraft stripper and citrus-strip don't seem to have any effect on it--any other suggestions? Pretty tough clear coat!

Lance M · 03-25-2014, 10:14 AM

I've tried every stripper and nothing worked to remove the clear coat from a new segment. Frank uses "All Pro Marine Remover". There is a place in Houston that carries it.
I ended up sanding it off with a DA sander and continuing wet sanding with finer and finer grits 400-1500 grit before polishing.

AtomicNo13 · 03-25-2014, 11:30 AM

The new units don't use a clearcoat. It is supposedly a bonded film applied by Alcoa at the time of manufacture. From what I hear it burns off in a few seasons them you can polish away!

Lance M · 03-25-2014, 11:56 AM

A coating that is clear is a "Clear Coat" to me. There are many different types of clear coat, but it is still a clear coat whether is is bonded, sprayed, dipped or other means.
I can assure you from experience, that this coating will not burn off in a year or two. Maybe 15 years or more, but not less than 10.

This subject has been discussed thoroughly on this thread.

AtomicNo13 · 03-25-2014, 12:00 PM

Hogwash.... I had a 6 month old classic bought back and replaced due to the fact the " clear coat" burned off. Trailer was manufactured 16 days prior to my purchase. I had a replacement in my hands within 9 months. I can assure you it can does and will burn off fast.

Lance M · 03-25-2014, 12:07 PM

Quote:

Originally Posted by AtomicNo13

The new units don't use a clearcoat. It is supposedly a bonded film applied by Alcoa at the time of manufacture. From what I hear it burns off in a few seasons them you can polish away!

Quote:

Originally Posted by AtomicNo13

Hogwash.... I had a 6 month old classic bought back and replaced due to the fact the " clear coat" burned off. Trailer was manufactured 16 days prior to my purchase. I had a replacement in my hands within 9 months. I can assure you it can does and will burn off fast.

So you DO have experience with this? Thanks for clearing that up.

AtomicNo13 · 03-25-2014, 12:21 PM

In fact I just recently discovered a big patch on my 09 PanAm where the film has failed.... Total heartbreak!
It lives inside out if the sun. Never been in salt, mag chloride, or wet other than a wash. I'll post pictures when I get home.
Conversely my 1991 excels is in constant use, lives on the roar mostly all the time. Only has a few issues from where the clear was scratched by the po.

Belegedhel · 03-25-2014, 12:31 PM

Hmmm...must be the cosmic rays in the thin air of Colorado. Down here in Houston, I think I would have to wait a long time for this slightly downward facing segment to lose its coating naturally. It is so perfectly bonded, that I didn't even suspect that it had a clear coat on it. Some how I managed to install the panel without scratching the coating--and it isn't because I'm careful (my new unofficial name for my trailer is the "Errstream").

Erik Olson · 03-25-2014, 12:35 PM

This is a great thread! Would a 1974 Ambassador have the factory clear-coat? I'm going to try the toothpaste trick. Does regular test Colgate work or is it brand-specific. Also, is it the aluminum going black in the test area or the toothpaste turning black?

AtomicNo13 · 03-25-2014, 12:35 PM

Err stream lol

Belegedhel · 03-25-2014, 12:41 PM

The 70's vintage trailers had clear coat applied to them, but by now, much of it has probably disintegrated and washed away. You will likely need to use a stripper on the vertical sections, but the more horizontal sections may already be clear coat free. The best toothpaste to use is the old opaque "pasty" type, not a gel. The black stuff is aluminum oxide that is coming off. If there is a clear coat, then you won't do anything but smear toothpaste on your trailer. It takes a few minutes of rubbing to get the oxide moving.

AtomicNo13 · 03-25-2014, 12:48 PM

I don't have anything your vintage but I believe you have the plasticote type clearcoat.

Belegedhel · 03-25-2014, 01:23 PM

The clear coat that was on the majority of my '73 bubbled up at the touch of the Aircraft stripper. The stuff that is on the "new" segment is bullet proof--seems to be invulnerable to any chemical--I'll try the Marine stripper if I can find it and it has anything more hostile than the Aircraft stripper, otherwise, I'll be breaking out the sand paper.

lisaslists20 · 07-07-2014, 06:30 PM

So, it's been 6 months. What happened to the new panel? Did you sand? How did it go?
Lisa

lisaslists20 · 07-07-2014, 06:30 PM

oooops. it's been 3 months, lol.

Belegedhel · 07-07-2014, 08:33 PM

Well, I started working on the interior, thinking that I would get back to the exterior once I have a bed to sleep on. I did buy some Marine stripper stuff, but I am not sure that it is the stripper of myth and legend--I'll give it a try here pretty soon...

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